This invention relates to a method for reducing metal oxides, and more particularly to a method of reducing iron oxides in which the oxides are reduced in several steps.
It is broadly old to produce molten steel by passing iron ore through a plasma arc torch and collecting the torch effluent in a refractory-lined crucible containing a slag. However, the high temperature heat in the plasma stack gases was wasted. In addition, it was found that the reduction of the ore in the torch was relatively incomplete; hence, the slag was rich in iron oxides, resulting in severe corrosion of the crucible refractory as well as a potential loss of iron.
It is an object of this invention to provide a method in which the heat in the off-gas from the plasma arc torch is utilized and in which the temperature of the gas is reduced to a level where it can be handled with conventional materials.
It is a further object of this invention to provide a method of reducing iron oxides in which the reduction of the oxides is substantially completed in a plasma arc torch.